This invention relates to an implantable electrical device having a lead connector assembly attached thereto and, more particularly, to implantable pacemaker/cardioverter/defibrillator devices having electrode-lead-receiving connector assemblies that are manufactured separately from and thereafter connected to the remainders of the devices.
The invention will be described herein in connection with its use in a pacemaker system. However, it will be apparent to those skilled in the art that the invention has broader applicability to other implantable electrical devices in which a connector assembly is employed to connect electrical leads to electrical circuits.
The operation of an implantable heart pacemaker requires the transmission to the pacemaker of low level electrical signals generated by the heart, as well as the transmission to the heart of pacing voltages generated by the pacemaker. The pacer generally comprises a metal case within which electrical circuits are carried, and a connector assembly having terminal jacks therein which are connected to the electrical circuits within the metal case and into which terminal pins on the proximal end of an electrode lead are received.
Conventionally, connector assemblies are fabricated and installed upon metal pacer cans after the internal electrical circuits of the cans have been installed and the manufacturing of the can is otherwise completed. In adding the connector assembly to the completed can, the terminal jacks of the connector assembly are electrically joined to feed-throughs which extend from within the can to the area of the terminal jacks in the connector assembly. This type of prior art pacemaker system may be seen in U.S. Pat. Nos. 4,715,380 and 4,995,389 to D. L. Harris.
One problem extant with pacemaker systems of the type shown in the Harris patents is that the connector assembly thereof cannot be constructed without first providing the fully finished pacemaker can. Accordingly, the connector assemblies cannot be stocked. Also, if the feed-throughs are not properly electrically connected to the terminal jacks, or if one of the wires connecting the feed-throughs to the terminal jacks breaks, the effort and expense encountered in manufacturing the pacemaker can is wasted since the feed-throughs, the can, the connector assembly and the electrical circuits within the can will all be rejected. This is a costly process which would be desirable to avoid.
Another problem extant in prior art pacemaker systems may be seen in U.S. Pat. No. 4,934,366 to D. E. Truex and W. H. Stutz, Jr. In this case the electrode-lead-receiving terminal jacks are incorporated within a barrel assembly that is, itself, positioned within the metallic case of the pacemaker so that the feed-throughs employed in the Harris type pacemaker systems are eliminated. One disadvantage resulting from this type of pacemaker system is that the overall size of the pacemaker is larger than it would be if the Harris type system is employed. Moreover, at present there is an increasing demand for smaller units having a larger number of electrode lead connectors therein. This makes the Truex and Stutz type of pacing system impractical.
It is, therefore, a primary object of the present invention to provide for improved connections between the connector assemblies and the cases of pacemaker systems.
It is a further object of the present invention to accommodate a large number of lead connectors in a small connector assembly.
It is another object of the present invention to facilitate the separate manufacture of pacemaker case units and connector assembly units, each of which units are provided with cooperating plug-in features that allow them to be assembled together upon completion of the manufacture of such units.
It is yet another object of the present invention to provide for improved attachment of and electrical connections between sealed connector assemblies and sealed electrical-circuit-containing cases of implantable electrical devices.
Further objects and advantages of this invention will become apparent as the following description proceeds.